1. Field of the Invention
The present invention relates to an apparatus for the automatic concentration control of an aqueous caustic soda solution which is used in the continuous treatment of a long cloth.
2. Description of the Prior Art
In subjecting a long, commercially produced cloth to such treatments as pretreatment, weight reduction and mercerization continuously, it is common to soak the cloth to be treated with an aqueous caustic soda solution having a prescribed concentration in a cloth treating tank and then to subject the resultant cloth to treatments such as, heat and tension treatments. In such a treatment with the use of a caustic soda solution, however, a drawback exists such that the quality of the treated product becomes uneven due to the fact that the concentration of the caustic soda solution changes frequently during the course of treatment.
Therefore, it is necessary in such a continuous treatment of a cloth, to apply a caustic soda solution having a definite concentration. However, in transporting a long cloth continuously through a cloth treating tank containing a treating solution, the concentration of the caustic soda solution unavoidably becomes lower with time. Conventionally, therefore, the caustic soda concentration in the treating solution tank is determined manually at prescribed time intervals, and a supplementary caustic soda solution is supplied into the cloth treating tank based on the result of the determination of the controlled concentration of the caustic soda solution in the cloth treating tank. However, with such a manual operation, problems arise; one being that a skilled operator is needed and another being that a long time is necessary until the solution control is completed thus deteriorating the operation efficiency.